What Is Polarization of Light?

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Light is an unusual object, when considered by physics. It has properties of a particle and of a wave. The basic unit of light is the photon, and it is this that gives it its particle properties. One the other hand, because the photon is so small, it can also be described by quantum physics as being a wave, which causes it to behave like an energy beam that can oscillate in many directions.

The polarization is a property of waves that describes the orientation of its various oscillations. For the purposes of transverse waves, it describes its oscillations perpendicular to the direction that the wave is traveling. An easy way to visualize this is to imagine a wave moving away from you. Axes that are perpendicular to the direction of this wave would then appear to be left to right and up and down.

Because light is a transverse electromagnetic, it can be visualized, by the example above, as having left to right and up and down components. In reality, many oscillations of light have aspects that are both left to right and up and down. Light that has oscillations in all directions is known as unpolarized light. For light to become polarized, one of these axes (either up and down or left to right) must be removed.

The simplest way to polarize light is via the use of a polaroid filter. A polaroid filter is made up of material which can block one of the axes of light oscillation (again, either up and down or left and right). As a result, a polaroid filter removes half of the light's waves. As a result, the polarized light has only have the intensity of its unpolarized counterpart, and only vibrates in a single plane (either up and down or left and right). If light is passed through two filters that block out a different axis, no light will shine through.

Light can also be polarized via other means. When light reflects off of non-metallic surfaces, polarized light will emerge. If the polarization is extreme, "glare" will be observed. When light passes from one material to another, it is called refraction, which will also cause some polarization of the light. Additionally, when light travels through a medium it will hit the atoms and "scatter," causing other waves to be set off. These waves will interfere with the light on certain planes, causing it to polarize.